Vanes in rotary compressor pumps in current use are formed of specialty cast iron or high-speed cutting steel, but vanes made of these materials are very expensive because it is required to machine the entire vane structure.
In certain applications, vanes formed of sintered materials are being used. In spite of the low cost of these vanes, the presence of residual austenite structure due to the presence of nickel makes them unsuitable for use in high-load pumps because of their poor performance in wear resistance and seizure resistance.
Iron and steel materials can be provided with improved wear resistance by peforming quenching and tempering. However, attempts to apply these heat treatments to sintered alloys have not met with much success because of insufficient real pressure due to the presence of pores in the sintered alloys.